The Collaborative International Dictionary of English v.0.48:
Pyrgom \Pyr"gom\, n. [Gr. ? a place furnished with towers, fr. ? a tower.] (Min.) A variety of pyroxene; -- called also fassaite. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Fassaite \Fas"sa*ite\, n. (Min.) A variety of pyroxene, from the valley of Fassa, in the Tyrol. [1913 Webster]